It should be used with caution, and only under medical supervision. The goal of this medication is to increase your response to sexual stimulation by increasing the blood flow in your penis allowing you to get an erection. Make sure you tell your doctor about all of the health issues you have and the medications you’re taking. There are a number of reasons why sildenafil (Viagra), vardenafil (Cialis), and Stendra may stop working. Testosterone products should only be used under a doctor’s guidance, as it’s important to monitor one’s testosterone levels. Tadalafil starts working anywhere from 15 to 45 minutes after you take it. There are generic versions of sildenafil, verdenafil and tadalafil available. Interestingly, while ED is often thought of as a condition that affects middle aged and older men, around a quarter of all men under 40 experience ED on a regular basis. When a man becomes sexually excited, muscles in their penis relax. Buy cialis 20 mg Online Pharmacy without a doctor's prescription. Cialis comes in yellow, film-coated and almond-shaped tablets in 5, 10 and 20 milligram (mg) doses. Erectile dysfunction disorder is one of the most common sexual problems for men and the percentage of men with this problem increases with age. You take this PDE5 inhibitor about 30 minutes before sex, no more than once per day. Men who do not have erectile dysfunction should not use alprostadil as a sexual aid. Some laboratory side effects of testosterone replacement therapy include changes in blood cholesterol, increased red cell count, and a decrease in sperm count (which can produce infertility, especially in younger men). They work by inhibiting an enzyme called phosphodiesterase type 5 (PDE-5), allowing more blood to enter the penis and helping to produce an erection. The most common side effect of these medications is a headache. Men who have penile erections lasting longer than two to four hours should seek Emergency Room care. Speak openly with your doctor, so he/she can help you find the best choices for treatment.